This invention relates to vehicle monitoring systems and in particular a system capable of monitoring the weight of a vehicle, such as a transport truck, and displaying or indicating this weight to either the driver of the truck or to a remote monitoring station.
At the present time, the only method known to the applicants for monitoring truck traffic along public highways is the use of publicly operated inspection stations provided with weigh scales and located at strategic locations along the highway. A number of problems have been encountered however with the operation of the present stations, perhaps the major one being that in peak traffic periods they are unable to handle the large volumes of commercial vehicles without lengthy delays. The delays are caused apparently by the length of time it requires to weigh these large commercial vehicles which can be quite long and the time required to manually log details concerning the vehicle such as its license class, manifest and violations committed. The problem might be overcome by providing greater facilities at these vehicle stations or by increasing the manpower but this could only be done at a considerable increase in costs to the public or to highway users, and governments are under increasing pressure to keep unnecessary costs down as much as possible.
Another problem with the present vehicle monitoring system is that because of manpower or labour union requirements, the present inspection stations are only open during certain hours of the day and therefore they are unable to monitor vehicles during off hours such as during the night. If a system could be found to automatically and quickly check and process commercial vehicles, it might be possible to have such inspection stations operate 24 hours a day either with no manpower at all or with very minimal staff.
A further problem with the present operation of highway inspection stations is that in order to catch violators or trucks that exceed their maximum allowed weight, it is generally necessary for the authorities to impose a rule that all commercial vehicles turn off the highway and into the inspection station facilities so that each vehicle can be checked. This is true even though many of the vehicles might have already gone through an inspection station at some other location earlier during the same trip. It will be appreciated that for a truck to have to stop at several such stations during the course of a single trip may result in the trip requiring considerably more time and fuel than would otherwise be the case. These extra costs must eventually be passed on to those hiring or using the commercial vehicles.
Vehicle monitoring systems of various sorts are known at the present time but as far as applicants are aware such systems have not been developed for use by commercial transport vehicles in order to overcome the aforementioned problems that the owners of these vehicles face. For example U.S. Pat. No. 4,251,801 issued Feb. 17, 1981 to U.S. Philips Corporation describes a communication system in which a fixed station consecutively interrogates a fleet of vehicles by the sending and receiving of messages. A receiver of the fixed station effects for each vehicle in turn synchronism with the reply messages transmitted by the relevant vehicles. The system appears to be designed for a fleet of vehicles such as buses. The use of coded messages for transmission over the airwaves is also disclosed.
Recent U.S. Pat. No. 4,303,904 issued Dec. 1, 1981 to Norman E. Chasek describes a system for facilitating the collection of tolls from the operators of motor vehicles. In order for the system to operate, the amount of money that is paid for toll purposes is recorded in the machine. As the vehicle passes the toll collection point, a toll transponder receives billing information from the vehicle transponder, calculates the toll payable, transmits this information back to the vehicle transponder where the toll is electronically subtracted from a stored balance. If the resulting balance is not negative, a pass signal is passed. This known system also employs three different codes in the vehicle's permanent memory.
U.S. Pat. No. 4,398,172 issued Aug. 9, 1983 to Eaton Corporation teaches a monitoring system designed for rental cars. A unit mounted in each vehicle includes circuitry for transmitting, on a continuous repetitive basis, information characterising the vehicle and unique thereto. A monitoring unit mountable at the monitoring location includes circuitry for receiving information transmitted by the vehicle unit. The unit in the vehicle can transmit information as to the mileage of the vehicle and as to fuel tank level, which information is required before the driver can leave the vehicle with the company.
An object of the present invention is to provide a vehicle monitoring unit for installation in a vehicle, such as a transport truck, whereby government transport authorities can quickly and easily monitor truck traffic in their territory.
A further object of the invention is to provide a vehicle monitoring unit for installation in a vehicle that includes means for sensing physical parameters of the vehicle including the weight thereof.